Re:Intel FP security issue
by ericseppanen on Wednesday June 13, 2018 @07:46PM
(#17308027)
Wasn't 212b02125f3 ("x86, fpu: enable eagerfpu by default for xsaveopt") sufficient protection for everyone on a modern CPU?
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That commit disables the lazy mode by default on processors supporting the XSAVEOPT instruction. But, it's possible to override that default with the eagerfpu= kernel command-line option, or that a hypervisor has masked out support for that instruction even on hardware with XSAVEOPT support.
The point is: although relatively unlikely, it is still _possible_ that you need some mitigation even if you have newer hardware (Sandybridge or newer is where XSAVEOPT first showed up, I believe).
Disclaimer: I work on Linux at Intel.